The role of the Molecular and Cytogenetic Pathology Core is to provide dedicated molecular biological and cytogenetic services to the Program Project Grant investigators. The services provided in this core are those needed in addition to standard clinical care and will provide molecular testing for projects monitoring treatment outcome and defining treatment complications. Molecular testing for chromosomal abnormalities or their transcription products will be performed for Projects I, II, and VI as an adjunct to standard cytogenetics on leukemia and lymphoma specimens and for the assessment of minimal residual disease. For Project I, PCR studies will also be performed for assessment of chimerism following allogeneic bone marrow transplantation. For Project II, various molecular genetic and cytogenetic techniques will be used to assess genome stability or induced cytogenetic changes to identify patients who may be predisposed to development of MDS or AML. For Project VI, this core will develop and employ highly specific, tailored, diagnostic reagents directed against the junctions of rearranged immunoglobulin gene segments in multiple myeloma and non-Hodgkin's lymphomas. We will also perform DNA PCR for t(14;18) for patients in Projects II and VI. The methodology required for conventional cytogenetics, FISH, RT-PCR and DNA PCR are routinely employed by the core investigators, who have also contributed to the molecular characterization of genetic markers in leukemias and lymphomas throughout the course of previous studies. The centralized performance of molecular and cytogenetic procedures by this core will avoid duplication of efforts in the program and ensure timely, efficient and consistently high quality results.